Any have experience with qt5 and custom .css?

Can you hit me up please, needing some advice and help on sorting a custom .css file for qt5 apps to use a reasonable sized icon. At the moment they are gigantic and I would like to style them to around 24-32px size.

I’ve found if I create a custom .qss file in the Style Sheets section of qt5ct with the following:

QToolButton { width:16px; height: 16px;}

I can change icon size, but nothing smaller than 45px which is huge.